Final answer:
The presence of the North's military did contribute to the prevalence of the Black Codes and Jim Crow laws in the South after the Civil War.
Step-by-step explanation:
The presence of the North's military did contribute to the prevalence of the Black Codes and Jim Crow laws in the South after the Civil War. These laws were enacted by the southern states to maintain white supremacy and restrict the rights and freedoms of African Americans. The North's military presence created tension and resistance from the white population in the South, leading to the strengthening of these discriminatory laws.